(1) Field of the Invention
The present invention relates to an adhesive tape joining method, which is used in the case where, for example, an adhesive tape is joined to a curved workpiece such as a door sash in an automobile, and an adhesive tape joining apparatus for use in the method.
(2) Description of the Related Art
In recent years, there has been developed a technique of joining a black adhesive tape in place of black coating applied to a door sash in the process of manufacturing an automobile. There has been proposed means for supplying and joining an adhesive tape, which is formed into a curved shape in conformity with a curve of a tape joined surface in a workpiece, to a pressing roller while a joining apparatus is moved along the workpiece under guidance (see, for example, JP-A 2001-328573).
The above-proposed adhesive tape joining apparatus has a feature in that the adhesive tape can be smoothly joined onto the curved workpiece without requiring any large-scale equipment. However, it still has plenty of room for improvement in joining performance at the curved portion of the workpiece.
That is to say, in the above-proposed apparatus, the supplied adhesive tape is inserted into a tape guide formed between a pressing roller (i.e., a joining roller) and an openable tape guide plate, and then, is wound around the pressing roller, to be thus guided to a portion to be joined. In this manner, the adhesive tape travels through the tape guide in a state held between the pressing roller and the tape guide plate.
When the adhesive tape passes the curved portion of a tape joined surface in the workpiece as the joining work proceeds, the curved portion of the adhesive tape in conformity with the curve of the joined surface also is supplied under the guidance. However, as described above, a winding starting portion of the adhesive tape around the pressing roller is held between the pressing roller and the tape guide plate, and further, the pressing roller is covered with a rubber-like elastic member, thereby reducing the slidability of the surface and making it difficult to shift the adhesive tape, so that the adhesive tape is turned into a restricted state in which the orientation or position of the adhesive tape is hardly changed. Consequently, when the curved portion of the adhesive tape is guided at the portion restricted as described above, a side end edge of the tape is strongly pressed or scraped against a positioning surface, and as a result, a crease is liable to be generated on the adhesive tape. Therefore, when the adhesive tape passes the curved portion at the tape joined surface, the adhesive tape is made to pass slowly and carefully while taking well the timing between the moving speed of the apparatus and the change in posture of the apparatus. Thus, a further improvement has been desired from the viewpoint of handability.